Hydroductor



c. A. GONGWER HYDRODUCTOR Filed July 22, 1950 INVENTOR. V $LV/N1A6ONGWER BY M42 ATTORNEY March 5, 1963 AMIQ Om United States Patent Ohiice Patented Mar. 5, 1953 3,079,753 HYDRGDUCTGR Calvin A. Gengwer, Azusa, Califi, assignor, by mesue assignments, to Aerojet-General Corporation, Azusa, Qalilh, a corporation of Ghio Filed July 22, 195i), Ser. No. 175,397 3 Guitars. (83!. 65-656) This invention relates to jet propulsion and more particularly to the underwater propulsion of vessels such as projectiles.

A principal object of the invention is to provide a propulsion system for a submarine device of the class described, capable of a long range of travel and at higher velocities than are ordinarily possible.

A related object is to provide a device which can opcrate at greater depths without losses in etficiency and power in comparison with its operation at or near the surface.

A further related object is to provide such a device capable of operation without a gaseous wake.

A further object is to provide a device having a minimum of moving parts, and which can be cheaply constructed, and can be stored ready for firing even though the storage periods may be prolonged for a considerable period of time.

The usual types of underwater devices, such as torpedoes, which have heretofore been in common use, have generally been impractical for operation at great depths; and even though they may operate eifectively within a few feet of the surface of the Water, their propelling efficiency is seriously afiected when the degree of submergence becomes appreciable.

Other disadvantages which have attended the use of ordinary torpedoes and other similar underwater craft are: that they have been easily detectable by sonic picku s; their speed has been relatively slow; their driving mechanisms were generally complicated and required a considerable number of moving parts, many of which were sensitive to fine adjustments; and they gave a gaseous walre.

In accordance with my present invention, 1 overcome these d advantages of previously known torpedoes and submarine type missiles; and I carry this out by providing a device which is capable of effective operation even at very great depths, the depth being limited only by the strength of the materials of which the unit is made. Furthermore, my device is capable of operating even more efficiently at great depths of submergence than near the surface.

i carry out my inven n by the provision of a duct into which water from the medium may flow, and ordinarily the duct will be in a streamlined or tormdo-shaped housing to minimize water resistance. The duct comprises a reaction region to the rear of which there is located an exhaust nozzle. in proximity to the reaction region, there is located a propellant charge of the selfcornbustible type which produces substantially no permanent gases and which will ordinarily be a solid or substantially a solid.

in accordance with a feature of the invention, means is provided for conveying water from the medium to the combustion re ion such that the heat of combustion or reaction of the propellant vaporizes the water, and the pressure in the combustion region forces this water vapor or steam rea wardly. ?referably, this water-conveying means is in the form of a conduit leading from a forward position into the combustion chamber.

In accordance with a related feature, the Water conveycd into the chamber is under a ram pressure due to the movement of the device through the water.

In accordance with another related feature, a spray injector is provided to spray the water into the chamber.

Another preferred feature resides in the provision of an adaptation of the steam injector pump principle at the rear of the nozzle, the injector providing means for the entry of more water from the medium to commingle with the steam and condense the steam so that substantially no vapor leaves the device. A preferred feature of the injector resides in a difiuser arrangement to provide effective relationship of the pressures.

An important advantage and feature of the device is that it can be operated Without releasing gaseous prod nets of combustion; and this is of a special advantage in the case of torpedoes and the like, used in war time.

The foregoing and other features of my invention will be better understood with reference to the etailed description and accompanying drawings in which:

FIG. 1 shows an end view of the device looking at the forward end;

FIG. 2 is a cross section view of the device taken on the line 2-2 of P16. 1;

FIG. 3 is a cross section taken on the line 3-3 of H6. 2 showing the manner in which the water injector is secured to the exhaust nozzle portion;

FIG. 4 is an enlarged plan view showing the water sprayer; and

FIG. 5 is an end View of the iniector shown in FIG. 4.

The device shown in the drawings comprises a torpedoshaped body itl provided with an inlet opening 11 at its forward end and a venturi-shaped exhaust nozzle 12 at its rearward end. The torpedo body is essentially divided into three compartments: a forward compartment 13, an intermediate compartment 14, and a rear compartment 17. The forward compartment 13, in which may be carried some form of payload, such as an explosive charge, is separated by a partition or partitions 16, from the intermediate compartment 14 in which is stored a propellant charge 15. The compartment or space 17 is located between the rear end of the propellant compartment and the exhaust nozle l2; and this space 17 serves as a reaction chamber which increases in size as the propellant charge is burned.

A tube 13 is attached to tire inlet opening 11 and is preferably positioned symmetrical to the longitudinal axis of the torpedo, so that it passes axially through compart ment 13, partitions 16, compartment l4 and extends into the reaction chamber 17. The rearward end of the tube 18 is provided with a spray device 15* having a plurality of orifices or openings 29 through which water entering the tube 13 is discharged into the reaction chamber 17.

A constant flow control valve 21 is located within tube 18, and this serves to keep the amount of water entering the reaction region through the spray device, substantially constant throughout the operation regardless of variation in the rate of travel. A portion of the stream passing through the constant flow control valve 21 in tube 18 is conducted by a conduit 21a to an annulus 21b in the region of the forward portion of the exhaust nozzle 12. Annulus 21b is connected to the diminishing region of the nozzle by a plurality of small injector orifices Zi a. These introduce Water into the throat or constricting portion of the exhaust nozzle 3.2. This Water is used to keep the nozzle free of solid encrustation from the residue of the burning propellant.

A conical member 22 which, together with the exhaust nozzle 12, forms a steam injector and having a larger forward diameter than the diameter of the discharge end 23 of the exhaust nozzle 12 is positioned to overlap the rear end of nozzle 12, thereby providing an annular opening 24. The diameter of member 22 then decreases as it progresses downstream until it reaches the throat 26 of the diffuser portion 27, and the difluser is preferably made to er iarge slightly between the throat 2'6 and the outlet end 28.

A plurality of fins 29 are fastened to both the augmentor 2 2 and the body of the projectile 10 and these fins secure the augmentor 22 in fixed relationship with respect to the nozzle 12.

In the drawings the missile is assumed to be an unguided missile and if desired could be spin-stabilized by providing a twisted or spiral configuration to the fins sufiicient to enable the projectile to follow a straight line trajectory. However, this is not necessary to the invention and any system of controls found to be satisfactory could be used.

It is desired that the propellant charge should generate no uncondensable gaseous products during the reaction, therefore, only those fuels or oxidizers which produce substantially solid or liquid combustion products should be employed. While all metals which are capable of reacting with an oxidizer to form a solid or liquid reaction product are usable, it is preferable to employ those metals which have a low molecular weight and at the same time are capable of releasing a large amount of heat per gram of fuel. The most ideal fuel for this purpose is aluminum metal, which has a molecular weight of only 27; and yet when it is oxidized to A1 it is capable of releasing 2.49 Kcal/gram of propellant when reacted with potassi- 11m perchlorate.

Aluminum reacts with potassium perchlorate in the following manner:

8Al+3KClO 4A1 O +3KCl +2.49 Kcal/ gm. of propellant The propellant charge can be made by intimately mixing a powdered oxidizer and a powdered metal until the mixture is substantially homogeneous. The mixture can then be placed in a mold, cylindrical in form, and the metal and oxidizer mixtureis subjected to a pressure which preferably lies between 50,000 and 100,000 lbs. per square inch; although it has been observed that in some cases pressures as low as 30,000l bs. per square inch are suflicient to cause the mixture to bind itself into a solid mass. The pressure intimately packs the fuel and oxidizer together and the ductile aluminum or other metal binds itself satisfactorily with the oxidizer under this pressure, forming a grain that is for all practical purposes free of voids and does not require any other binder to hold it together. Since the charge is required to burn in a restricted or controlled manner, that is, with a burning rate which remains substantially constant throughout the operation, and burning on only the desired faces of the grain, it is usually desired to protect the outer circumferential surface of the grain from burning. can be accomplished by placing the powdered fuel and oxidizer within anon-water reactive metal shell such as, for example, a thin copper jacket and then subjecting the jacket and the mixture to the high pressures mentioned above. This causes the charge to bind itself together and at the same time to bind itself to the jacket, and also to the tube 18 if the tube beset within the propellant mixture before the application of the pressure. In order to permit passage of the tube 18 through the propellant charge and at the same time to provide a satisfactory inner liner for the charge, the charge may be cast or formed around a small inner tube of suflicient diameter.

Another way in which the charge may be utilized is to insert the powdered mixture into the propellant chamber of the device and then subject the chamberand the powdered mixture to the elevated pressures. This, or any other way of lining or preventing the burning of the circumferential surface and other surfaces which'are not to be permitted to burn, is satisfactory.

Themanner in which the device operates is as follows: The projectile with its charge of compressed metal and oxidizer is launched into the water at high velocity. The

ram pressure, causing the Water to enter tube 18, pass through the flow control valve 21 and spray through the openings 20. A firing squib 39 located at the rear of the propellant charge is fired by some suitable means, such as are well-known, at the time the projectile is launched. One way of firing the squib, for example, is to make it of a water-reactive material, so the reaction will'start spontaneously at the time the sprayed water comes in contact with the squib. Such a squib may be a mass of water-reactive chemicalsuch as sodium or the like. The combustion of the squib generates sufficient heat to start the reaction between the metal and oxidizer in the charge;

a and the reaction once started will continue unabated until all of the propellant charge has been consumed.

The required propellant charges are those which producesubstantiallyonly solid products of combustion and heat when burned, which heat converts the water, continuously spraying through the orifices 250, into steam.

a t s of t swind thmneh th wate devel a The steam under pressure escapes through-the nozzle 12 and impinges in the chamber 31 against the water which is enteringthe injector through the annular scoop 24. By the time the steam and water mixture has reached the throat 25 virtuallyall-of the steam should be condensed to Water and a substantial portion of velocity of the steam will thus have been transferred to the water. The veloc ity of the water at this point will be greater than the original spouting velocity 'of the water entering the scoops 24 but will be less than the velocity of the steam jet. The pressure at the throat 26 and in the chamber 31 should then be approximately equal to the equilibrium pressure of the mixture of water and steam which will be a very low value becauseof the large amount of cold water present.

Downstream from the throat 26 where the passageway undergoes a slight gradual expansion to the exit opening, this enlargement serves as a diffuser and is sufiicient to cause some of the velocity head to change into static pressure which is desired for discharging the jet against the existing external static pressure. The area of the entry scoop 24 and the amount of the enlargement in the diffuser section should preferably be designed to be selfadjusting so as to vary with the depth of submersion which may vary over wide limits; and with this in mind, good design proportions can be selected. This may be accomplished by tapering the lip 24a of the conical member 22 to form a section of decreasing thickness which becomes very thin as it approaches the end. The thin lip is deflected bythe external pressure of the water acting upon it, thereby decreasing the area of the opening as the external pressure increases upon submersion to greater depths.

An important factor in the operation is that the 'intro duction of Water into the reaction chamber is insured.

When the device is travelling at high speeds, for example, knots minimum, the ram head acts against the water in the tube and places the water under sufiicient pressure to cause it to'be injected into the reaction chamber against the pressure developed by the restriction provided on the exit of the steam by the nozzle 12. In this type of device no water pump is required; and that operation can be started by either launching it at high velocities or providing an auxiliary water injection in the reaction chamber until the velocity is sufiiciently great to develop the necessary ram pressure.

Another outstanding characteristic is the fact that the propellants which have been referred to generate only heat and solid products of combustion; the heat being used to convert the water into steam and the solid products being exhausted through the nozzle'and the diffuser. The propellant charge burns cigarettewise thereby insuring aconstant burning area and burning rate on its rear exposed surface.

Since the direction of the flow in the case of both water entering through the scoops land the steam escaping through the exhaust nozzle lies; in the same general direcamazes tion, the two fluid streams impinge each other in an impact in which the total momenta of the water and of the steam streams are conserved in the momentum of the resulting stream of water and condensate at 26.

The phenomenon that the efficiency becomes greater at substantial depths than at shallow depths may be in part explained by the fact that the back pressure acting on the steam nozzle is very low. This back pressure is the saturation pressure of the mixture of condensate and condensing water. Furthermore as the depth increases, the condensing water entering the device through the scoops 24 spouts into the condensing chamber 31 from the surrounding medium at increasing velocities. This causes the impact between the steam and water to take place with more kinetic energy being transferred from the steam jet to the stream of condensing water. This is due to the fact that the steam velocity is many times greater than the velocity of the water; and the mass rate of flow of the steam is many times less than that of the water; in accordance with the law of conservation of momentum, a substantially constant velocity increase is therefore given to the mass of water. Since the water has an initially high velocity, and in addition is given an additional velocity, the kinetic energy of the water mass is much higher than if the same velocity increase were transferred to a slower moving mass of water. This is because kinetic energy increases with the square of the velocity. In this manner, the energy of the steam is more effectively transferred to the condensing water as the depth increases and as a result, higher energy is obtained in the jet formed by the combined condensate and condensing water. This results in a higher exit velocity and more thrust is developed, other things being equal, as the depth of submersion increases.

Among the advantages of my invention are the fol lowing: It is capable of operating at very great speeds; and the efiiciency increases as the depth of submersion becomes greater, a feature which has heretofore been unknown in underwater heat engines. The device possesses no moving parts or valves with the possible exception of the flow control valve and the depth compensation for the scoops, therefore, requires no careful adjustment or expensive repair. The fuel and oxidizer charge can be pressed into a rigid grain which is insensible to wide temperature variations and may be instantly employed regardless of the length of time the grain may have been stored.

A particular feature of the invention which is of importance in naval operations during war time is that the device operates without the creation of a gaseous wake, and it is therefore difficult to detect its presence.

Another feature is that the energy density of the compressed propellant 8Al+3KClO exceeds 6 Kcal/cc. and this together with the good thermopropulsive efficiency provided gives an unusually high value of propulsive horse power hours available from a missile of given size. This is reflected by permitting the development of small missiles of long range and high speed.

It should be understood that the description and drawings employed in the above specification are given by way of example rather than of limitation; and the invention is not limited except by the scope of the appended claims.

I claim:

1. A jet propulsion device for operation in water, comprising a duct housing having a first water inlet opening and a first exhaust nozzle, a reaction chamber between said inlet opening and said first exhaust opening and adjoining said first exhaust nozzle, water conduit means connecting said first water inlet opening and said reaction chamber, a solid propellant charge within said housing surrounding said conduit means and adjoining said reaction chamber, and a member means having a second water inlet opening, a second exhaust nozzle behind said second water inlet opening and a duct connecting said second water inlet opening and said second exhaust nozzle, said member means being positioned downstream from said first-mentioned exhaust nozzle, and the forward end of said member means surrounding the rear end of the first-mentioned exhaust nozzle, the rear end of the conduit means entering the reaction chamber, a water spraying means attached to said rear end, and a flow control means Within said conduit means to control the flow of water to a constant value, whereby water entering the reaction chamber from the conduit means is vaporized by the heat of reaction of the propellant charge, then passes through the first exhaust nozzle, and then condenses in the member means, causing water to flow out the second exhaust nozzle to produce the propulsion.

2. A jet propulsion device for operation in water comprising a reaction chamber, an exhaust nozzle at the rear of the reaction chamber, a self-combustible solid propellant charge in front of the reaction chamber and presenting a burning surface at the forward end of the reaction chamber, and a water conduit having an opening facing in the forward direction of motion to receive water under ram pressure during the forward motion, said conduit being a substantially straight tube extending from the nose of the device and coaxially through the device and into the reaction chamber to expel its water in said rc action chamber, whereby the heat of reaction vaporizes the water to steam which is expelled rearwardly through the exhaust nozzle.

3. A jet propulsion device for operation in water comprising a reaction chamber, an exhaust nozzle at the rear of the reaction chamber, a self combustible solid propellent charge of a type which produces no permanent gases in front of the reaction chamber and presenting a burning surface at the forward end of the reaction chamber, and a water conduit having an opening facing in the forward direction of motion to receive water under ram pressure during the forward motion, said conduit leading into and expelling its water into the reaction chamber, whereby the heat of reaction vaporizes the water to steam which is expelled rearwardly through the exhaust nozzle, and a member attached to the exit of said exhaust nozzle, said member comprising a passageway substantially co-axial with the nozzle and having a larger cross section at its forward end than at its discharge end, there being left a space between the forward end of the member and the outside of the discharge nozzle through which water from the medium may enter the member, said member being provided with a diffuser, said diffuser comprising a throat area somewhat forward of the discharge end of the member and of somewhat smaller cross section than that of said discharge end, and depth compensating means to adjust the area of the space with varying depths of submersion, said depth compensating means comprising a thin lip at the forward end of the member adapted to be deflected toward the exterior of the exhaust nozzle by water pressure.

References Cited in the file of this patent UNITED STATES PATENTS 1,253,597 Hitt Jan. 15, 1918 1,315,352 Torazzi Sept. 9, 1919 1,680,451 Chandler Aug. 14, 1928 1,688,761 Sperry Oct. 23, 1928 2,351,750 Fawkes June 20, 1944 2,461,797 Zwicky Feb. 15, 1949 2,479,470 Carr Aug. 16, 1949 2,522,113 Goddard Sept. 12, 1950 2,544,422 Goddard Mar. 6, 1951 FOREIGN PATENTS 3,468 Great Britain of 1898 123,245 Great Britain Feb. 20, 1919 397,992 Great Britain Sept. 7, 1933 602,807 Great Britain June 3, 1948 

1. A JET PROPULSION DEVICE FOR OPERATION IN WATER, COMPRISING A DUCT HOUSING HAVING A FIRST WATER INLET OPENING AND A FIRST EXHAUST NOZZLE, A REACTION CHAMBER BETWEEN SAID INLET OPENING AND SAID FIRST EXHAUST OPENING AND ADJOINING SAID FIRST EXHAUST NOZZLE, WATER CONDUIT MEANS CONNECTING SAID WATER INLET OPENING AND SAID REACTION CHAMBER, A SOLID PROPELLANT CHARGE WITHIN SAID HOUSING SURROUNDING SAID CONDUIT MEANS AND ADJOINING SAID REACTION CHAMBER, AND A MEMBER MEANS HAVING A SECOND WATER INLET OPENING, A SECOND EXHAUST NOZZLE BEHIND SAID SECOND WATER INLET OPENING AND A DUCT CONNECTING SAID SECOND WATER INLET OPENING AND SAID SECOND EXHAUST NOZZLE, SAID MEMBER MEANS BEING POSITIONED DOWNSTREAM FROM SAID FIRST-MENTIONED EXHAUST NOZZLE, AND THE FORWARD END OF SAID MEMBER MEANS SURROUNDING THE REAR END OF THE FIRST-MENTIONED EXHAUST NOZZLE, THE REAR END OF THE CONDUIT MEANS ENTERING THE REACTION CHAMBER, A WATER SPRAYING MEANS ATTACHED TO SAID REAR END, AND A FLOW CONTROL MEANS WITHIN SAID CONDUIT MEANS TO CONTROL THE FLOW OF WATER TO A CONSTANT VALUE, WHEREBY WATER ENTERING THE REACTION CHAMBER FROM THE CONDUIT MEANS IS VAPORIZED BY THE HEAT OF REACTION OF THE PROPELLANT CHARGE, THEN PASSES THROUGH THE FIRST EXHAUST NOZZLE, AND THEN CONDENSES IN THE MEMBER MEANS, CAUSING WATER TO FLOW OUT THE SECOND EXHAUST NOZZLE TO PRODUCE THE PROPULSION. 